Some of the best uni is known to come from Japan and processed by uni processors mostly in Hokkaido, Japan. Every uni processor has their own "secret" way of processing uni to maintain its sweetness and keeping the uni intact so it doesn't melt in transit. 

Uni is extremely sweet and rich with umami flavor. In Japan, it is served mainly as sushi, gunkan or donburi (over rice), but in other countries it used as sauce. "Jou" uni is easier understood as "A Grade". Grading in uni is mainly based off of size, color and texture of each tongue or piece of uni. "Tokujou" can be referred to as AA Grade. Usually consists of bigger sized tongues with more vibrant colors. Grading is determined by each processor and can vary by different processors. Each piece is delicately separated by the processors and then neatly arranged in the tray. "Narabi" means lined up in a uniform way while "Bara" means not lined up in a uniform way. Typically "Narabi" carries a higher grade, but some processors do "Bara" style trays so they can use less chemicals and allow the more "natural" taste of uni to come out.

Bitterness in uni typically comes due to issues when the uni is in transit from Japan to the US. Since uni is extremely fragile, sudden shake or the box it is packaged in falls, it can taint the quality. You taste the "myoban" or alum that is used to process the uni to keep it intact.

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